So I'm about to run a session in two weeks from now. Got the free pdf of Death House from WotC's website, and was thinking of incorporating it into some part of Sigil, to add to the weirdness of the city. A house come alive thanks to some mysterious entity that traps any trespassers and demands sacrifice. I would also link part of its story with my upcoming adventure, Doors to the Unknown, along with lore needed to better understand a few things about Sigil and its history (Aoskar, the dabus, portals etc.). But then, it occurred to me that there was an area in Planescape: Torment with a similar, albeit morally ambiguous, situation, the Alley of Lingering Sighs. So my thought went like this:

There was this wealthy family who, along with a few friends, formed a cult of Aoskar, deep in the house's basement. It didn't take long, though, for rumours to circulate about the illegal, however unfounded, acts of the family. Even though the family was accused of preying on poor sods from the Hive Ward, any investigations from the Harmonium turned up nothing suspicious. But people started avoiding the place and the alley, and the area soon fell into disarray. It was then that the Lady of Pain showed herself outside the house, and none heard anything about the sinister cult ever since. But, a millennia after the incidents, the Death House still lingers, in a secluded alley, dubbed The Alley of Lingering Sighs. Many times it was burned to the ground, only to rise from its ashes again and again. The locals claim that the alley is haunted by the evil spirits that still inhabit the Death House, luring any unsuspecting traveller into its dark bowels, never to be seen again.

My question is, do we know anything about the Alley of Lingering Sighs, apart from what is presented in the video game?

Righto, thanks rip! Guess I'll use my imagination to detail the whereabouts of the alley.
It could go something sort of a failed ritual, as the desperate cult was attempting to contact their dead god, and even bring a semblance of life to their house. Soon after The Lady showed up, the barmies were sent to their Maze, but not before their magic somehow affecting the alley, and bestowing it with its own entity. Centuries of incubating in the walls of this blind alley, all the while defending itself against the dabus constantly trying to alter it, and the efforts of the crazed cagers who wished it burnt down, it found a way to free itself by splitting its existence and, in order to do that, certain sacrifices should be made.